Apparatus for singularizing stacked portions of books and the like

Abstract

Apparatus for singularizing successive stacks of a series of stacks consisting of superimposed groups of sheets has a transporting unit which advances successive stacks of the series in a horizontal plane against a barrier which intercepts each but the lowermost group of the oncoming stack. An endless conveyor with one or more pushers is provided to advance successive lowermost groups of an intercepted stack through and beyond a clearance between the barrier and a stationary table of the transporting unit. The width of such clearance exceeds the height of a single group but is less than the combined height of two superimposed groups. The width of the clearance and the extent to which the pusher or pushers can extend above the horizontal plane are adjustable. The apparatus further comprises a gate which is pivotable behind an intercepted stack to a position in which it prevents advancement of a fresh stack toward the table and can bias each but the lowermost group of an intercepted stack against the barrier, and a raised position in which the conveyor of the transporting unit is free to deliver a fresh stack toward and into engagement with the barrier. The barrier is adjustable toward and away from the gate.

I claim: 
     
       1. Apparatus for singularizing a series of stacks of superimposed groups of sheets wherein each group has a predetermined height, comprising means for transporting successive stacks of the series above a predetermined plane in a predetermined direction along a first path; a barrier extending transversely of said path above said plane and defining with said plane a clearance having a width between n and 2n wherein n is the height of a group so that the barrier intercepts each but the lowermost group of an oncoming stack; means for advancing successive lowermost groups of a thus intercepted stack, including at least one pusher and means for moving said at least one pusher along a second path including a top portion wherein the at least one pusher extends above said plane a distance at most equaling n and advances toward said clearance from a position behind an intercepted stack, said moving means comprising an endless conveyor having an upper reach which is substantially parallel to said plane and defines the top portion of said second path, and a lower reach which defines a second portion of said second path at a level beneath said plane for advancement of said at least one pusher back to said position thereof; and means for varying the level of the top portion of said second path. 
     
     
       2. The apparatus of claim 1, wherein the top portion of said second path extends in said direction beyond said clearance. 
     
     
       3. The apparatus of claim 1, further comprising a gate extending substantially transversely of said first path and means for moving said gate between a first position in which said gate is located in said first path behind an intercepted stack and a second position outside of said first path. 
     
     
       4. The apparatus of claim 3, wherein said gate is pivotable between said first and second positions thereof. 
     
     
       5. The apparatus of claim 3, wherein said gate is located above the top portion of said second path in said first position thereof. 
     
     
       6. The apparatus of claim 3, wherein the means for moving said gate includes means for urging the gate against each but the lowermost group of an intercepted stack in the first position of said gate. 
     
     
       7. The apparatus of claim 1, wherein said moving means further comprises a stepping motor for said conveyor. 
     
     
       8. The apparatus of claim 1, wherein said varying means includes elevator means for said moving means. 
     
     
       9. The apparatus of claim 1, further comprising means for varying the width of said clearance. 
     
     
       10. The apparatus of claim 9, wherein said varying means includes elevator means for said barrier. 
     
     
       11. The apparatus of claim 1, further comprising means for adjusting said barrier in and counter to said predetermined direction. 
     
     
       12. The apparatus of claim 1, further comprising a conveyor positioned downstream of said clearance to receive groups which are advanced by said at least one pusher. 
     
     
       13. The apparatus of claim 1, wherein said transporting means comprises an endless conveyor and a table downstream of said conveyor, said barrier being disposed above said table. 
     
     
       14. Apparatus for singularizing a series of stacks of superimposed groups of sheets wherein each group has a predetermined height, comprising means for transporting successive stacks of the series above a predetermined plane in a predetermined direction along a first path; a barrier extending transversely of said path above said plane and defining with said plane a clearance having a width between n and 2n wherein n is the height of a group so that the barrier intercepts each but the lowermost group of an oncoming stack; means for adjusting said barrier in and counter to said predetermined direction; and means for advancing successive lowermost groups of the intercepted stack, including at least one pusher and means for moving said at least one pusher along a second path including a top portion wherein the at least one pusher extends above said plane a distance at most equaling n and advances toward said clearance from a position behind an intercepted stack. 
     
     
       15. The apparatus of claim 14, wherein said second path includes a second portion along which said at least one pusher advances toward said position by moving at a level beneath said plane. 
     
     
       16. The apparatus of claim 14, wherein said moving means comprises an endless conveyor having an upper reach which is substantially parallel to said plane and defines the top portion of said second path, and a lower reach which defines a second portion of said second path at a level beneath said plane for advancement of said at least one pusher back to said position thereof. 
     
     
       17. The apparatus of claim 16, further comprising means for varying the level of the top portion of said second path. 
     
     
       18. The apparatus of claim 11, wherein said adjusting means comprises an elongated carrier for said barrier and guide means defining for said carrier a third path for movement in and counter to said direction. 
     
     
       19. Apparatus for singularizing a series of stacks of superimposed groups of sheets wherein each group has a predetermined height, comprising means for transporting successive stacks of the series above a predetermined plane in a predetermined direction along a first path; a barrier extending transversely of said path above said plane and defining with said plane a clearance having a width between n and 2n wherein n is the height of a group so that the barrier intercepts each but the lowermost group of an oncoming stack; means for advancing successive lowermost groups of the thus intercepted stack, including at least one pusher and means for moving said at least one pusher along a second path including a top portion wherein the at least one pusher extends above said plane a distance at most equaling n and advances toward said clearance from a position behind an intercepted stack, said second path including a second portion along which said at least one pusher advances toward said position by moving at a level beneath said plane; a gate extending substantially transversely of said first path; and means for moving said gate between a first position in which said gate is located in said first path behind an intercepted stack and a second position outside of said first path, said means for moving said gate comprising means for urging the gate against each but the lowermost group of an intercepted stack in the first position of said gate.